Mini-Review; Stress Genes: An Introductory Overview

Molecular sequence data, made available in the last 15 years or so, have led to the classification of living cells into three phylogenetic domains: Bacteria, Archaea, and Eucarya. All the organisms that have been tested belonging to either domain were capable of mounting a stress response with essentially the same characteristics, regardless of the stressor. The protagonists in the cell's stress response are the stress genes and their protein products. Some of the latter are molecular chaperones. Under physiological conditions, these chaperones aid other cellular proteins to fold properly and achieve a native -functional- configuration, and to translocate from the place of synthesis to the cell's locale in which they will operate. In a stressed cell, the stress proteins that are chaperones protect other molecules from denaturation and help those partially damaged to regain a functional configuration. Thus, cell death is avoided and recovery is enhanced. The study of stress genes and proteins has progressed considerably in organisms belonging to the domains Bacteria and Eucarya. Less is known about the archaeal stress genes. Here, research with an organism from the Archaea is discussed, focusing on the stress genes of the hsp70 (dnaK) locus. Future perspectives for basic and applied research within the health sciences and biotechnology industries are presented.     

Attenuation of Hippocampal 11beta-Hydroxysteroid Dehydrogenase Type 1 by Chronic Psychosocial Stress in the Tree Shrew

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) catalyses the interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone, thus regulating glucocorticoid access to intracellular receptors. In rats, chronic glucocorticoid excess or stress increases 11beta-HSD-1 in the hippocampus, producing suggestions that it may attenuate the deleterious effects of chronic glucocorticoid excess. However, 11beta-HSD-1 predominantly catalyses 11beta-reduction in the intact liver and hippocampal cells, thus regenerating active glucocorticoids from inert substrate. We studied 11beta-HSD activity in the tissues of male tree shrews following 28 days of sustained psychosocial stress or exogenous administration of cortisol. In the hippocampus, chronic psychosocial stress attenuated 11-HSD-1 activity (69 +/- 9% of control), whereas cortisol alone had no effect. In the liver, both chronic stress and cortisol administration decreased 11beta-HSD-1 activity (47 +/- 11% and 49 +/- 4% fall, resp.). Attenuation of 11beta-HSD-1 within tissues may reflect a homeostatic mechanism designed to minimise the adverse effects of prolonged stress and/or glucocorticoid excess.     

Role of Glucocorticoids on Rat Brain Metallothionein-I and -III Response to Stress

The metallothionein (MT) gene family consists of four members (MT-I through -IV) that are tightly regulated during development. Whereas MT-I and MT-II are widely expressed isoforms, MT-III has been found to be mainly expressed in the central nervous system in adult animals, and is the only isoform that inhibits survival and neurite formation of cortical neurons in vitro. A number of models of brain injury have been shown to affect MT-III mRNA levels, which has been suggested to be related to the putative neurotrophic role of this protein. However, a stress response will presumably be associated to the brain injury which could, in turn, drive MT-III regulation. In the present report the effect of a classical stress model, immobilization stress, on brain MT regulation has been studied in rats. MT-I+II protein levels were measured by radioimmunoassay in up to eight brain areas and, as expected, it was found that stress increased selectively MT-I+II levels. Adrenalectomy (ADX) had a general decreasing effect on basal MT-I+II levels; however, ADX blunted the MT-I+II response to stress in cerebellum and presumably in frontal cortex and medulla plus pons but not in the hypothalamus. MT-I mRNA measurements were in accordance with the MT-I+II protein levels in the brain areas studied. In contrast to MT-I mRNA, MT-III mRNA levels of brain cortex tended to decrease during stress, although this effect was not statistically significant. ADX also tended to decrease basal MT-III mRNA levels. Northern blot assays of pooled mRNAs suggested similar differential regulation of these two brain MT isoforms in the cerebellum. These results indicate that glucocorticoids mediate brain MT-I+II response to stress in some but not all brain areas, that a role of these hormones is likely also for MT-III, and that the regulation of MT isoforms differs substantially in the brain.     

Cognitive rehabilitation of chronic alcohol abusers

The current literature suggests that individuals who chronically abuse alcohol exhibit a wide variety of cognitive deficits resulting from cerebral dysfunction that is either directly or indirectly related to their alcohol consumption history. Cognitive deficits have been hypothesized as having implications for standard alcohol treatment efficacy as they may directly affect cognitively impaired individuals’ abilities to utilize various treatment modalities. Although evidence is accumulating that suggests this is actually the case, the majority of alcohol treatment programs neither directly consider the impact cognitive deficits have on treatment efficacy nor do they employ cognitive rehabilitation treatment strategies to remediate identified cognitive deficits. Few studies exist that investigate the remediability of neurobehavioral deficits or the efficacy of integrating cognitive rehabilitation strategies into more traditional treatment programs. Empirical investigations conducted to date indicate that some cognitive deficiencies secondary to alcoholism are amenable to cognitive rehabilitation and this remediation is generalizable. Rigorous well-controlled treatment outcome investigations are needed in order to determine the efficacy of cognitive rehabilitation techniques in naturalistic settings using ecological outcome measures. Also, emphasis should be placed on integrating cognitive rehabilitation techniques with proven efficacy into traditional alcoholism treatment programs.     

A Comparison of Active Student Response and On-Task Instruction on the Acquisition and Maintenance of Health Facts by Fourth Grade Special Education Students

An alternating treatments design was used to compare the effects of active student response (ASR) and on-task (OT) instruction on the acquisition and maintenance of health facts during small-group lessons. Five students with learning difficulties (4 students identified as developmentally handicapped and 1 student identified as learning disabled) participated in daily instruction on weekly sets of 20 unknown health facts (10 facts assigned to the ASR condition and 10 to the OT condition). During ASR instruction, the teacher modeled the correct response to a health question that was presented visually on a health fact card, and the students immediately repeated the correct response in unison three times. During OT instruction, students attended visually to the health fact card as the teacher modeled the correct response. All 5 students made more correct responses on end-of-day tests on health facts taught with ASR instruction than they did on health facts taught with OT instruction. ASR instruction also produced consistently superior results on maintenance tests administered 2 weeks after instruction.     

Gender, object, and humor

Male and female respondents rated jokes with either a female initiator/male target of joke or vice versa. For male respondents, the gender of the joke target made no difference. For female respondents, however, jokes with males as the target received significantly higher ratings than jokes with females as the target.     

Effects of Self-Correction on the Acquisition, Maintenance, and Generalization of the Written Spelling of Elementary School Children

We examined the effect of self-correction on the acquisition, maintenance, and generalization of written spelling of elementary school students attending an after-school clinic. Six students registered for remedial tutoring participated. During self-correction, students initially learned four proofreading marks and a procedure for using them that were subsequently applied as the students compared their spelling to a model. Results showed a functional effect between self-correction and improved student performance on target words. Using the self-correction procedure, the students spelled at least 98% of the target words accurately, maintained at least 85% of the correctly spelled words, and generalized at least 70% of the words at home, in context, and with word variations. Questionnaires administered to the students, their parents, and teachers indicated that students preferred self-correction. Parents noticed academic improvements in their child's spelling performance as well as positive changes in attitude toward school. Most teachers did not notice changes in spelling performance or attitude.     

Lateralized Changes in Regional Cerebral Blood Flow during Performance of Verbal and Facial Recognition Tasks: Correlations with Performance and “Effort”

Functional neuroimaging has been used to investigate neural substrates of mnemonic processes, and cerebral blood flow (CBF) measures have been sensitive to activation with memory tasks. Studies of memory with two-dimensional¹³³Xenon clearance techniques found that word and face recognition tasks produced contralateral CBF changes in mid-temporal cortical regions. This study replicated the activation paradigm, expanding to the three-dimensional resolution of positron emission tomography (PET). Word and face recognition, and a control baseline task were administered to 19 healthy right-handed volunteers (11 men, 8 women) during successive 10 min PET¹⁵O-water measures of CBF. Quantitative CBF rates were calculated with the arterial input function and the equilibrium model. Redistributions of blood flow were compared across tasks using both absolute and relative (region/whole brain) CBF.Replicating the¹³³Xenon clearance findings, CBF was “appropriately” lateralized during task performance (left–right for words > left–right for faces) in the mid-temporal region. Contrary to predictions, the recognition tasks did not activate expected mesolimbic or prefrontal areas. The task-induced CBF changes also correlated with performance. Bilateral CBF in mid-temporal and parahippocampal gyrus regions of interest correlated with the ability to correctly identify word targets (sensitivity). Left-lateralized CBF in the amygdala and hippocampus correlated with better word sensitivity as well as specificity (ability to correctly reject foils). Complementally, right-lateralized CBF in the parahippocampal gyrus correlated with better face specificity performance. In addition, left-lateralized CBF in the amygdala and right-lateralized CBF in the parahippocampal gyrus and hippocampus correlated with “mental effort” indices (task performance relative to basal ability) for word and face memory tasks, respectively. Thus, whereas this recognition task showed the expected lateralized increase in the mid-temporal region and not in frontal and limbic areas, lateralized activation in some of these areas was associated with better performance. Exploratory analyses on other regions showed lateralized changes in one additional temporal region, the occipital-temporal, and several limbic regions.     

Gender, relational role orientation, and affinity for animal rights

Research based mainly on non-national samples reports a greater affinity for animal rights among women than men, and proposes a greater relational role orientation among women that emphasizes caring for others to explain this difference. Using a recent national sample comprised of 11% African American and 89% white American respondents, we find that a relational role orientation fails to account for women’s greater support of animal rights. It does provide minor help in distinguishing animal rights advocates from nonadvocates, but only among women and only on one of two measures of animal rights support. We conclude by proposing women’s structural locations as well as the interplay between these locations and women’s role socialization as alternate explanations for gender differences in affinity for animal rights.     

Rape Myth Acceptance and Sociodemographic Characteristics: A Multidimensional Analysis

Many myths have been identified surrounding rape, rapists, and rape victims. This study reexamines the acceptance of rape myths across gender role ideologies and selected demographic characteristics to identify core myths. Three myth categories were established and investigated: blaming the woman, excusing the man, and justifications for acquaintance rape. Findings indicate that rape myths remain prevalent and adherence to myths is related to demographic factors and gender role attitudes. Overall, respondents tend to excuse the man more than blame the woman. Males accept rape myths more than females. Racial differences emerged most strongly on the justifications for acquaintance rape dimension. Individuals with a conservative gender role ideology believe rape myths more than those with more liberal ideologies. While core myths did not emerge from the data, the most revealing finding is that summative scaling techniques used in previous studies may mask important differences, between and within the three dimensions, in rape myth acceptance among the groups studied.